Adjustable gas key for autoloading firearm

ABSTRACT

Aspects herein relate to a system for controlling the flow of gas to a moving parts assembly in an autoloading firearm cycled at least in part using gas produced from firing of the autoloading firearm. The system can include means for establishing fluid communication with a gas source providing the gas during at least one portion of the firearm firing cycle, a conduit of the means for establishing fluid communication including an inlet corresponding to the gas source and an outlet directing at least a portion of the gas toward the moving parts assembly, and a means for modifying the flow of gas through the conduit. Also provided are methods for making and using adjustable gas keys.

TECHNICAL FIELD

The disclosures herein relate in general to firearms. More particularly, aspects herein relate to autoloading firearms which are operated at least in part by gases from firing.

BACKGROUND

Since the invention of firearms, shooters have sought to increase the efficiency of the firing process. One aspect of such efficiency is the speed between shots, which is partially a function of any reloading that must occur before subsequent firing, as well as the time required to bring the direction of fire back to the target based on changes from a previous shot.

Multi-barreled firearms were an early solution to expedite the speed with which a subsequent shot could be fired. The following centuries brought revolvers containing multi-shot cylinders and manually-cycled repeating arms such as lever- and pump-action weapons having tubular magazines. Internal box magazines were employed with multi-shot bolt rifles. Later, firearm designers successfully harnessed the forces of firing, permitting the firearm to cycle its action automatically with each trigger pull, thus introducing autoloading firearms. The development of clips, belted ammunition, and detachable magazines cemented the superiority of the autoloading firearm in the decades that followed.

As shooters can now fire several cartridges without conducting manual reloading actions, the limiting factor in subsequent shots is frequently a shooter's ability to properly aim the weapon at the target. Recoil (and other forces from firearm operation) frequently cause the muzzle direction to change after firing. Other factors (such as averseness to muzzle blast) can further influence a shooter's ability to maintain the sights on the target. Accordingly, shooters frequently seek modifications or enhancements to aid in control of the firearm during shooting.

Further, some modifications or accessories (such as suppressors) change the forces at work on the firearm during firing. It is therefore at times desirable to change aspects of the firearm's function (e.g., modify the flow of gas) to better accommodate such modifications or accessories.

SUMMARY

Aspects herein include a system for controlling the flow of gas to a moving parts assembly in an autoloading firearm cycled at least in part using gas produced from firing of the autoloading firearm. The system can include means for establishing fluid communication with a gas source providing the gas during at least one portion of the firearm firing cycle, a conduit of the means for establishing fluid communication including an inlet corresponding to the gas source and an outlet directing at least a portion of the gas toward the moving parts assembly, and a means for modifying the flow of gas through the conduit.

Embodiments of a method for making an adjustable gas key include providing a gas key having an attachment portion, an angled portion, and an upper interface, the attachment portion operatively couples the gas key to a moving parts assembly of an autoloading firearm cycled at least in part using gas produced from firing of the autoloading firearm, the angled portion directs at least a portion of gas from firing the autoloading firearm toward the moving parts assembly, the upper interface maintains fluid communication with a gas source during at least a portion of the autoloading firearm firing cycle, and forming an adjustment aperture in fluid communication with the conduit incident to at least a portion of the conduit.

With gas keys as disclosed herein, there can be embodiments of a method of adjusting a firing characteristic of an autoloading firearm cycled at least in part using gas produced from firing of the autoloading firearm, comprising modifying a flow of gas resultant to firing of the autoloading firearm within a gas key.

Various aspects will become apparent to those skilled in the art from the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a system including a bolt carrier group for an autoloading firearm.

FIG. 1B illustrates an exploded view of the bolt carrier group of FIG. 1A.

FIG. 2 illustrates a cutaway view of the bolt carrier group of FIG. 1A.

FIG. 3A illustrates a solid view of a gas key of the bolt carrier group of FIG. 1A.

FIG. 3B illustrates a cross-sectional view of a gas key of the bolt carrier group of FIG. 1A.

FIG. 4 illustrates a solid view of an embodiment of an adjustable gas key disclosed herein.

FIG. 5 illustrates a cross-sectional view of an embodiment of an adjustable gas key disclosed herein.

FIG. 6 illustrates a cross-sectional view of an embodiment of an adjustable gas key disclosed herein.

FIG. 7 illustrates a cross-sectional view of an embodiment of an adjustable gas key disclosed herein.

FIG. 8 illustrates an embodiment of a methodology for producing an adjustable gas key disclosed herein.

FIG. 9 illustrates an embodiment of a methodology for modifying a firing characteristic of an autoloading firearm using an adjustable gas key disclosed herein.

FIG. 10 illustrates an embodiment of a methodology for calibrating a firing characteristic of an autoloading firearm using an adjustable gas key disclosed herein.

DETAILED DESCRIPTION

The disclosures herein generally relate to an adjustable gas key for an autoloading firearm. The adjustable gas key can selectively restrict the flow of gas through the gas key to a moving parts assembly, thereby modifying firing characteristics of the weapon.

As used herein, an autoloading firearm can include any firearm which will chamber another cartridge after firing without manual action from a firearm operator (e.g., semiautomatic, automatic) provided ammunition is available (via, e.g., a magazine, belt). While the distinction is readily appreciated with reference to bolt- or lever-action firearms, such also distinguishes from, for example, a double-action revolver to the extent that pulling of the trigger performs the mechanical action of cycling the cylinder. The cycle of autoloading firearms (e.g., “firearm firing cycle”) is discussed in greater detail below.

The M-16 service rifle is generally referred to herein as the example system on which an adjustable gas key is utilized. Those of ordinary skill in the art will appreciate the variants of this system, and the applicability of such disclosures to the same. For example, the M-4 carbine and countless variants of the AR-15 rifle are other platforms chambered in the 5.56×45 mm NATO (or similar .223 Remington) cartridge which use identical or near-identical parts to those of the M-16. Further, firearms such as the AR-10 (chambered in 7.62×51 mm NATO or similar .308 Winchester) and variants thereof use parts of similar design. While these calibers comprise a large proportion of firearms of this design, various complete firearms or modular kits are available to chamber rifles of this style in a wide variety of other calibers (e.g., .22 long rifle, 9 mm parabellum, 7.62×39, .300 Blackout, 6.8 mm Remington SPC, 5.45×39 mm, 6.5 Grendel, .458 SOCOM, .450 Bushmaster, .300 Whisper, .338 Whisper, .204 Ruger, .50 Beowulf). A large number of manufacturers produce components for such firearms or entire firearms of such patterns, including Rubber City Armory, Lewis Machine and Tool, JP Enterprises, Colt Defense, Armalite, Rock River Arms, Bravo Company Manufacturing, Bushmaster, CMMG, Daniel Defense, DPMS, FN Herstal, Heckler and Koch, Knight's Armament Company, Lame Tactical, Magpul, LWRC International, Mossberg, Noveske, Patriot Ordinance Factory, Remington, Sturm Ruger and Company, Sig Sauer, Stag Arms, Wilson Combat, Yankee Hill Manufacturing, and many others.

While the examples provided above generally belong to a single family or class of firearms (the M-16 type), and their differences are generally directed toward accommodating or retrofitting for particular sizes of cartridges and the forces associated with their firing, various other firearms having similarities in their moving parts assemblies can also be modified according to components and techniques herein. For example, the internal piston design M-16 type rifle is frequently compared to or conflated with direct impingement gas systems, for which disclosures herein may be adapted. In another example, variants of M-16 style rifles modify the moving parts to effect a blowback system for autoloading (e.g., kits modifying such firearms to accommodate 9 mm parabellum rounds). In this regard, aspects herein can be utilized with firearms operating using direct impingement gas systems, external pistons, blowback designs, alternative internal piston designs, or other mechanisms for effecting automatic loading without departing from the scope or spirit of the innovation, and nothing herein should be interpreted as limiting application of techniques herein exclusively to gas systems such as those illustrated.

M-16 type firearms and other autoloading firearms are typically designed to provide more than enough forces to moving parts than is required to properly cycle the firearm. For example, in M-16 type firearms, the gases force a bolt carrier group violently against a buffer and spring which compresses into a buffer tube. Residual force is absorbed by the buffer tube and/or stock (and ultimately the shooter) when the buffer and contacting bolt carrier group fully compress the spring against the end of the buffer tube. By providing excess force, the reliability of M-16 type firearms is increased, as it is more likely that the bolt carrier group will move a distance adequate to eject the spent casing and seat the bolt behind a new cartridge in the magazine. However, it is possible to reduce the force with which the bolt carrier group is propelled toward the buffer without compromising the ability of an M-16 type firearm to complete its cycle of operations.

As used herein, a “gas key” or “carrier key” is a mechanical part operably coupling two or more parts of a firearm gas system. For example, in the context of the M-16 style rifles, the gas key is a shaped form attached to a bolt carrier. The gas key mates with a gas tube in a receiver and redirects gases traveling from the gas tube downward into the bolt carrier. Those of ordinary skill in the art will appreciate gas keys in other firearm systems, which can be identified by the same or alternative nomenclature, which can be produced or modified in accordance with aspects herein.

As used herein, a “moving parts assembly” includes mechanical components (typically, but not necessarily, provided in the receiver or upper receiver of an autoloading firearm) which displace during the firing cycle (described in greater detail below) of the autoloading firearm to directly or indirectly accomplish various stages of the firing cycle (e.g., ejecting, cocking, chambering).

As used herein, an “adjustment aperture” indicates an aperture formed in a component deviating from a military or commercial specification for the component. For example, current carrier key specifications instruct production of a gas conduit with one inlet and one outlet. An adjustment aperture can be any additional aperture supplemental to the two means of reaching the space enclosed by the gas key necessary for function of the associated firearm. As used herein, an “adjustment control” is a mechanism for opening an adjustment aperture, closing an adjustment aperture, or selectively interrupting a path of fluid communication at least in part using an element provided through the adjustment aperture.

Modifications described herein are performed at least in part to augment at least one firing characteristic of an autoloading firearm. In this regard, firing characteristics can include felt or absolute recoil, perceived or absolute muzzle blast or flash, muzzle climb, torque or imbalance from firing, cyclic rate or aspects thereof (e.g., velocity of moving parts), pressure concentration or dissipation in components during firing, et cetera. More generally, firing characteristics can include any consequence to firing in terms of impact on the shooter, the cartridge, or the weapon.

Directional terms (e.g., rearward, forward, side, top, bottom, and others) in this application are generally intended to refer to directions in reference to a firearm held upright in a standard firing position. “Forward,” “front,” and similar terminology will refer toward the direction of bullet travel, or the muzzle-end of the firearm. “Rearward,” “back,” and similar terminology refers to the direction opposite bullet travel, or the stock-end of the firearm in firearms having a stock. The top of the firearm is the portion on which sights and/or carry handles are typically installed, and typically the highest-held portion when the weapon is in an upright firing position. The bottom of the firearm is the direction in which the trigger or pistol grip protrude from the receiver (e.g., a lower receiver).

“Operatively coupling” used herein describes components which act upon one another. Such action can be accomplished through mechanical interaction of solid components which are directly connected or which exert forces on one another through various linkages or at a distance. Such action can also be accomplished through fluid communication, which can be effected directly or through the direction of fluid matter through intervening or connecting components. Components or voids which are “incident” are those that intersect or couple. For example, an aperture is incident to a conduit when it passes through the wall of a conduit to establish at least partial connectivity between the two.

Turning to the drawings, FIGS. 1A, 1B, 2, 3A, and 3B generally show aspects of the prior art related to the gas system of an autoloading firearm. The gas system uses gases propelling the bullet down the barrel to cycle the action of the firearm by tapping the barrel such that some of the expanding gas returns to the receiver in a direction opposite the bullet's line of travel down the barrel.

Autoloading firearms can be described in terms of their firing cycle, or the various stages performed each time the weapon is fired and resets itself for subsequent firing automatically. In the example of an M-16 type rifle, the firearm has several steps in its firing cycle: firing, unlocking, extracting, ejecting, cocking, feeding, chambering, and locking. The rifle fires when a hammer strikes firing pin 158, which strikes a primer of a cartridge. The primer ignites the propellant in the casing, which rapidly expands. The expanding propellant separates the bullet from the casing and forces the bullet down the barrel. A gas block is attached to the barrel above a gas tap and includes a port into which gas tube 190 is disposed. The gas block includes a channel through which gas can pass into the gas block and to the gas tube from the gas tap. Therefore, no later than when the bullet passes the gas block of the barrel, some of the gases conveying the bullet exit the barrel via the gas tap interfacing with the gas block. These gases are then rerouted down gas tube 190 parallel to the barrel and re-enter the rifle's receiver. Gas tube 190 mates with upper interface 130 of gas key 102 (which may alternatively be called a carrier key).

After entering gas key 102, the gas travels through upper interface 130 and is turned into angled portion 120. Angled portion 120 includes carrier interface opening 122 which routes the gases from firing into carrier 150. This effects the second step of the cycle, unlocking, whereby the gases in carrier cylinder 168 of carrier 150 press bolt 170 forward and carrier 150 rearward. Specifically, pressure on gas rings 175 ensures bolt 170 remains seated in the chamber and prevents wear on locking lugs 171 while carrier 150 moves rearward. The rearward motion of carrier 150 causes translation of cam 166 in cam track 164. Cam 166 is seated in cam hole 179 of bolt 170 such that bolt 170 is rotated through the motion of cam 166. The rotation of bolt 170 causes locking lugs 171 to unlock, realigning to pass through the corresponding lugs of the chamber.

Once unlocking is completed, bolt 70 can travel rearward with the carrier 150 and exit the chamber. Extractor 172 exerts force on the rim of a cartridge while bolt 170 leaves the chamber and extracts the cartridge casing from the chamber. After extracting is complete, the cartridge casing is ejected from the receiver. Carrier 150 includes an angled face under firing pin 158, which forces the hammer down as carrier 150 moves rearward. The hammer is pushed down sufficiently to reengage the sear and is held in place until the next cycle of operation. This completes the cocking stage of the firing cycle.

The rearward motion of carrier 150 is controlled using a buffer and buffer spring. Once carrier 150 ceases rearward motion (i.e., by compressing a spring in a buffer tube), the spring causes carrier 150 to travel forward toward the chamber again. A cartridge from the magazine is permitted to advance upward under force from a spring-loaded magazine follower when bolt 170 moves rearward past the end of the cartridge, and stripped out of the magazine by the return of bolt 170 during the feeding stage of the firing cycle. The chambering step follows, whereby the stripped round is forced into the chamber of the rifle. The forward motion of carrier 150 behind the bolt now pressed into the chamber causes cam 166 to travel cam track 164, rotating locking lugs 171 into alignment with the chamber lugs, effecting locking of bolt. This completes the firing cycle, and the autoloading rifle is prepared to repeat the cycle for the next shot.

FIG. 1A specifically shows a system 100 including a bolt carrier group having carrier 150, bolt 170, and gas key 102. The bolt carrier group is shown in reference to charging handle 180, which gas key 102 nests in when assembled, and gas tube 190. Charging handle 180 is used for manual manipulation of the bolt carrier group, but does not reciprocate with the bolt carrier group during firing. Charging handle 180 can include a hole to permit one or both of gas key 102 and/or gas tube 190 to pass through a portion of one or more of its faces. The underside of charging handle 180 can be configured to overlay at least a portion of gas key 102, and the upper and/or outer surfaces can be sized and shaped to mate with a channel of a firearm receiver (e.g., upper receiver). Gas tube 190 is oriented parallel to a barrel and connects opposite the end shown to a gas block secured over a tap in the barrel which establishes fluid communication between the barrel and receiver by a route different from the barrel itself.

Carrier 150 operably couples the components of the bolt carrier group. When the bolt carrier group is assembled, carrier 150 houses bolt 170, which functions as an internal piston during the firing cycle described above. Gas key 102 is connected to carrier 150 using fasteners such as screws, which can be reinforced using various thread-locking substances, staking of the screw heads and/or attachment portion 110, or other means.

FIG. 1B shows an exploded view of the bolt carrier group of system 100. Visible in greater detail, gas key 102 includes attachment portion 110, angled portion 120, and upper interface 130. Upper interface 130 defines at least an opening of conduit 132, the space through which gas is routed from the gas tube, which is redirected through angled portion 120 down toward the carrier 150. Attachment portion 110 extends from angled portion 120, and facilitates attachment of gas key 102 to carrier 150. Attachment can be effected using, for example, one or more fasteners 114 which can extend through key fastener holes 112 into carrier fastener holes 156.

Carrier 150 includes a carrier cylinder 168 (better visible in FIG. 2) into which the gases from gas key 102 are projected by passing through carrier gas entrance 152. Carrier gas entrance 152 aligns with carrier interface opening 122 (better visible in FIG. 3B). Firing pin 158 is housed in carrier 150. Carrier 150 is formed such that the hammer swings through openings behind the firing pin to contact the firing pin without hitting carrier 150 (at least until after the pin is struck in each firing cycle). Firing pin 158 is held in carrier 150 using firing pin retaining pin 160, which nests in retaining pin hole 162. Carrier 150 can include one or more vent holes 154 to prevent overpressure in carrier 150 from gases vented into such, as well as effect collateral functions such as blowing open a dust cover which can be closed to isolate the opening of the receiver through which fired cartridge casings are ejected when no the weapon is not being fired. Additional gases may escape through other portions of carrier 150 (e.g., passage in which firing pin 158 is held, cam track 164) which are not fluidly sealed.

Carrier 150 includes cam track 164 in which cam 166 is inserted. When the bolt carrier group is assembled, bolt 170 is housed in carrier 150 through bolt opening 169, and cam 166 is also passed through cam hole 179 of bolt 170. When cam 166 is removed, bolt 170 spins freely in carrier 150, and can be removed entirely from carrier 150. With cam 166 installed, the motion of bolt 170 is defined by cam track 164, which limits translation and motion to a specific path matching the geometries of the chamber and receiver during firing.

Bolt 170 includes gas rings 175 which facilitate sealing of the bolt in bolt opening 169 of carrier cylinder 168 and enable the piston action of bolt 170. Bolt 170 also includes extractor 172, which is retained by extractor pin 173 and acted upon by extractor spring 174. In embodiments, extractor spring 174 can be supplemented with an o-ring or other compressible member to ensure the desired amount of resistance is applied by extractor 172 to the rim of a cartridge. Bolt 170 further includes ejector 176, coupled with ejector spring 177. Both ejector 176 and ejector spring 177 are retained by ejector pin 178.

FIG. 2 shows a cutaway view of the bolt carrier group of system 100. Carrier cylinder 168 in which bolt 170 moves can be better appreciated, as can the positioning of vent holes 154 in relation to the moving parts of the bolt carrier group.

FIGS. 3A and 3B show gas key 102 in isolation permitting appreciation for its details. While not each aspect of gas key 102 (or other components here) is expressly discussed, the major portions of gas key 102 are described as upper interface 130, angled portion 120, and attachment portion 110. Gas is received in upper interface 130, passing into conduit 132. Conduit 132 defines a path which redirects the gas at an angle through angled portion 120 toward carrier interface opening 122. Attachment portion 110 can include key fastener holes 112 to attach gas key 102 to a moving part of the gas system (e.g., carrier 150). Attachment portion 110 can have a wider dimension or cross section than at least upper interface 130, and can include various cutaway portions, recesses, flanges, bosses, et cetera. FIG. 3B in particular also shows gas tube 190 mated with upper interface 130.

With the general functioning of an example autoloading gas system now understood, FIGS. 4-7 show example embodiments of an adjustable gas key in accordance with the disclosures herein. FIG. 4 in particular shows one embodiment of an adjustable gas key 400 having attachment portion 410, angled portion 420, and upper interface 430. Upper interface 430 has an inlet wherein gas enters gas key 400 from a gas source (e.g., a gas tube). Angled portion 420 at least in part defines an outlet where gas can exit gas key 400 (e.g., into a bolt carrier group). Gas key 400 can be attached to moving parts of a firearm gas system using fasteners 414. Notably, gas key 400 includes adjustment screw 428 which can be moved screwed in or out of angled portion 420 and/or upper interface 430 to restrict the flow of gas through gas key 400. Additional details to this effect will be understood through discussion of FIGS. 5-7.

Various components described herein can be “lightweight” components. A lightweight component is one that has had material removed and/or is formed at least in part from materials differing from a standard specification part (e.g., military specification bolt carrier group) to reduce the mass of the component(s). Adjustable gas key 400 (and other adjustable gas keys herein) can be operatively coupled with a lightweight bolt carrier group or lightweight moving parts assembly via attachment portion 410. Because adjustable gas key 400 (and other adjustable gas keys herein) may reduce the amount of gas entering a moving parts assembly, lightweight components (and other complementary modifications such as reduced-coefficient springs or lightweight buffers) may be employed to ensure reliable cycling under reduced force from gas. Further, the use of lightweight components can further modify firing characteristics according to operator preferences.

While attachment portion 410 (and other attachment portions herein) are shown as accepting fasteners, it is understood that alternative mechanisms for providing a gas key to a moving parts assembly are embraced by the disclosures herein. For example, gas keys can be formed integrally on one or more parts of a moving parts assembly, such that attachment portion is a subcomponent of a larger continuous piece of material. In specific embodiments of such examples, not attachment portion may be discernible from other sections. Alternatively, attachment portion 410 could be welded, attached with adhesives, or operatively coupled with a moving parts assembly means other than those illustrated in FIG. 4 (or other figures).

FIG. 5 shows a cutaway view of an embodiment of a modified gas key 500 having an adjustment aperture 526 formed in angled portion 520 of gas key 500. In gas key 500, adjustment aperture 526 is formed through the rear-facing wall of angled portion 520. Adjustment aperture 526 may be left open to permit venting of gas passing through conduit 532 to the rear of gas key 500 during operation. In various embodiments, adjustment aperture 526 may be partially or wholly obstructed to change the amount of gases vented through adjustment aperture 526.

In alternative or complementary embodiments, an adjustment control can be provided at least partially through adjustment aperture 526 to modify the flow of gas through carrier interface opening 522 via conduit 532 (e.g., by redirecting or obstructing the passages through which gas can flow). However, the disclosures herein do not require that an adjustment control be provided through any one or more adjustment apertures in each and every embodiment. In alternative or complementary embodiments, other adjustment apertures can be provided in addition to adjustment aperture 526. While adjustment aperture 526 is shown formed in a specific location of gas key 500, it is understood that alternative positioning and orientation is embraced under the disclosures herein.

Attachment portion 510 is similar to other attachment portions herein, and includes gas key fastener holes 512. Likewise, upper interface 530 is similar to other upper interface portions herein.

FIG. 6 shows a cutaway view of an embodiment of a modified gas key 600 having an adjustment aperture 626 in combination with adjustment control 628. Adjustment control 628 can be variably inserted or removed through adjustment aperture 626 to open or close at least a portion of conduit 632. By changing the proportion of conduit 632 which is blocked by adjustment control 628, the amount of gas passing through carrier interface opening 622 to a moving parts assembly of an autoloading firearm. This in turn modifies firing characteristics of the firearm (e.g., by changing the distribution of forces throughout components during the firing cycle). The firing characteristics of the firearm can be modified in a binary fashion (e.g., gas permitted through or blocked) or through a continuous scale of quantity or quality (e.g., different amounts of gas blocked) through use of adjustment aperture 626 and/or adjustment control 628.

Adjustment control 628 can be hollow and/or include ports to permit gases to vent through adjustment control 628 (e.g., hollow screw). Adjustment control 628 may, in some embodiments be impermeable and block air entirely in spaces it occupies. Alternatively, adjustment control 628 may be partially permeable (e.g., constructed in part of a permeable material or perforated) and restrict only a portion of gases coming into contact with adjustment control 628.

Adjustment control 628 can be a screw matched to threading in adjustment aperture 626, the turning of which can open or close at least a portion of conduit 632. The screw can have various heads or other tool interfaces, or can include a portion which extends for hand-manipulation. Portions of the screw for its manipulation can be textured, knurled, magnetized, et cetera, to facilitate ease of turning, insertion, or removal.

In various embodiments, sizing of adjustment control 628 can be based on a dimension of angled portion 620, conduit 632, and/or other portions. For example, in an M-16 type autoloading firearm chambered in 5.56×45 mm NATO, gas key 600 is a standard gas key approximately 0.245 inches wide at angled portion 620. Therefore, embodiments of the adjustment control 628 are less than 0.245 inches, because any adjustment control widening the profile of angled portion 620 would fail to fit in the corresponding channel of the charging handle in which gas key 600 is disposed during operation. It is understood that, while dimensions may differ, the same principles apply in other chambering (e.g., AR-10 chambered in 7.62×51 mm NATO) of M-16 type rifles as well as in other types of firearms utilizing similar carrier keys.

In embodiments where adjustment control 628 is a screw and the autoloading firearm in which gas key 600 is integrated is an M-16 type rifle chambered in 5.56×45 mm NATO, examples of screw sizes that can be used include 1/16″, 3/32″, ⅛″, 5/32″, 3/16″, 7/32″, and other sizes smaller than the 0.245″ maximum dimension. Various alternatives (including metric sizes) can also be employed. Further, a system into which gas key 600 is integrated can be provided with two or more screws to facilitate additional adjustments based on screw design (e.g., length, tip profile, hollow/ported or solid, perforated or continuous).

Adjustment control 628 can alternatively be a button, snap, sliding member, or various others mechanical components which can be connected, disconnected, or moved through adjustment aperture 626 such that the flow of gas through conduit 632 is modified and adjustment control 628 withstands the forces of operation in the autoloading firearm.

Various embodiments can include coarser or finer adjustment means through use of adjustment aperture 626 and adjustment control 628. For example, in embodiments where adjustment aperture 626 and adjustment control 628 are threaded, finer or coarser threading, pitch, lead, or other thread variables can be modified to increase or decrease the number of turns required to displace adjustment control 628 by a specified distance, accordingly permitting finer adjustment of modifications to firing characteristics.

Adjustment control 628 can be configured to permit measuring or observation of adjustments, or display discrete adjustment amounts during use. For example, in embodiments where adjustment control 628 is a screw (or another mechanical component which is turned to modify its position at least with respect to conduit 632), one or both of adjustment control 628 and angled portion 620 can include markings indicating various angles or displacements. This assists an operator at least by providing knowledge of the absolute or relative position of an adjustment control 628 without requiring observation of firing characteristics.

In alternative or complementary embodiments, adjustment control 628 and/or adjustment aperture 626 can be toothed, notched, and/or coupled with detents or springs to facilitate detectable “clicks” associated with an amount of angular displacement or known position. For example, clicks can be set such that each tenth of a rotation is detected. Alternatively, clicks can be set at an open position, closed position, and/or arbitrary position therebetween. In this way, an operator can precisely and repeatably position adjustment control 628 for known and rapid modification of firing characteristics. In addition to providing known, measurable changes to adjustment control 628, such aspects can also retain the position of adjustment control 628 such that the setting of adjustment control 628 will not slip or be lost during firing or other manipulation.

Attachment portion 610 is similar to other attachment portions herein, and includes gas key fastener holes 612. Likewise, upper interface 630 is similar to other upper interface portions herein.

FIG. 7 illustrates an embodiment of a modified gas key 700, where in addition to adjustment aperture 726 and adjustment control 728, gas key 700 includes internal recess 729. Internal recess 729 may be an extension of adjustment aperture 726 into a portion of conduit 732 opposite the area of incidence between adjustment aperture 726 and conduit 732. Alternatively, internal recess 729 may be distinct from adjustment aperture 726 (e.g., in location, dimensions, profile). In some embodiments, internal recess 729 provides a space with which adjustment aperture 726 can mate. Such mating can be for purposes of strength or stability, to permit adjustment control 728 to be flush with or recessed below a surface of angled portion 720, to fully seal conduit 732, et cetera.

Alternatively, recess 729 can provide a curve path for gas to follow around adjustment control 728 partially obstructing conduit 732. By modifying the path, the distances, pressures, and velocities of operation may be varied to modify firing characteristics.

In some embodiments, conduit 732 can have a cross-section (cutting gas key 700 along a right-to-left line, from top to bottom and perpendicular to a line from front to rear) having at least one flat side or portion. Put another way, conduit 732 can be non-cylindrical or non-rounded, and can be formed to any arbitrary cross section provided the outer dimensions accord with the dimensions required for use in the autoloading firearm. In this way, tighter closing can be accomplished. For example, where conduit 732 has straight walls, adjustment control 728 of constant cross-section can fully close conduit 732 or portions thereof it interrupts. Alternatively, adjustment aperture 726 can be larger than conduit 732 in at least one dimension to permit full sealing through rounded side(s) with an adjustment control 728 larger than the widest dimension between the rounded side(s).

Attachment portion 710 is similar to other attachment portions herein, and includes gas key fastener holes 712. Likewise, upper interface 730 is similar to other upper interface portions herein. Attachment portion 710 ensures proper alignment between carrier interface opening 722 and a moving parts assembly to which modified gas key 700 is attached.

As noted, FIGS. 5-7 illustrate single adjustment apertures oriented through the rear-facing wall of angled portions of the respective gas key embodiments. However, one of ordinary skill in the art will appreciate that adjustment apertures and associated adjustment controls can be arranged at other locations on respective gas keys in alternative or complementary embodiments. While forming of the adjustment aperture in the illustrated location prevents the adjustment aperture and/or adjustment control avoids interference with contacting components (e.g., charging handle or gas tube) and permits easy access to the adjustment aperture (e.g., while the gas key is attached to a bolt carrier), other arrangements can be used in combination with or independent of the illustrated configuration. For example, additional apertures or porting can be used to facilitate the venting of gas if an adjustment control partially or wholly blocks a gas key's conduit. Alternatively, an adjustment aperture receiving an adjustment control can include various bevels or recesses about one or more edges, or other modifications to ensure unobstructed movement, airflow, or otherwise prevent damage or malfunctions. In this regard, alternative or additional adjustment apertures can be formed on an opposite side of an angled portion of a gas key, and/or on the top, bottom, or sides of any portion of a gas key.

In embodiments, further modifications may be committed to other components (e.g., porting of a gas tube, modification of a gas block) to ensure reliable and/or safe functioning of an autoloading firearm having a gas key with one or more adjustment apertures.

While aspects of FIGS. 5-7 are discussed in reference to single drawings, it is understood that various arrangements or embodiments are not exclusive, and that aspects can be combined, substituted, supplemented, et cetera, in various embodiments without departing from the scope or spirit of the disclosure.

Turning now to FIG. 8, illustrated is a methodology 800 for producing an adjustable gas key by forming an adjustment aperture in a gas key for an autoloading firearm. Methodology 800 begins at 802 and proceeds to 804 where a gas key for an autoloading firearm cycled at least in part using gas resultant to firing is provided.

At 806, an adjustment aperture is formed incident to a conduit of the gas key. The aperture can be formed in a prefabricated gas key using a drill, torch, punch or press, chisel, or other tool or technique known for creating holes in metals or other suitable materials.

Various alternative or complementary aspects can also be included in a method for making an adjustable gas key. For example, the adjustment aperture may be tapped or threaded to permit a threaded adjustment control to be inserted. Various other adjustment controls can be inserted, attached, or formed in or around the adjustment aperture. A screw, plug, or other adjustment control can be provided, inserted, or mated. In further aspects, an internal recess can be formed. In still further embodiments, two or more adjustment apertures and/or adjustment controls can be formed or provided in a single gas key.

Once forming of the adjustment aperture at 806 (and any subsequent aspects) are complete, methodology 800 ends at 808.

Turning now to FIG. 9, illustrated is a methodology 900 for modifying at least one firing characteristic of an autoloading firearm cycled at least in part with gas produced from firing. Methodology 900 begins at 902, where the gas flow through a gas key is modified using an adjustment aperture incident to the conduit through a gas key.

In at least one embodiment, gas is permitted to travel through at least a part of the adjustment aperture at 904 to reroute the gas from, for example, a carrier interface opening. In alternative or complementary embodiments, gas is blocked, slowed, or otherwise restricted at 904 using an adjustment control provided through at least one adjustment aperture.

Other aspects of methodology 900 can include opening or closing an adjustment aperture (partially or completely) and/or adjusting an adjustment control. For example, the amount of gas flowing through an adjustment aperture can influence firing characteristics, and the firing characteristics can be modified, tuned, or calibrated based on the amount of gas permitted to flow through the adjustment aperture.

Similarly, the amount and force of gas reaching a moving parts assembly through the gas key will influence firing characteristics, and accordingly the conduit of the gas key can be partially or wholly blocked (or unblocked) to permit modification, tuning, and calibration of firing characteristics. Thus, an adjustment control can be adjusted to effect such blocking or unblocking. Adjustment can be accomplished through turning (e.g., such as with threaded adjustment controls), pushing, pulling, and other mechanical action in reference to the adjustment control.

After the aspects described are complete, methodology 900 proceeds to end at 906.

FIG. 10 illustrates an embodiment of a methodology 1000 for calibrating a firearm in accordance with techniques herein. Methodology 1000 begins at 1002 and proceeds to 1004 where a firing characteristic is modified using an adjustment aperture. The firing characteristic can be modified by redirecting, venting, restricting, blocking, or otherwise changing the uninterrupted transmission of gas through the conduit of a gas key in accordance with aspects herein.

At 1006, a determination is made as to whether the firing characteristic has been modified such that the desired calibration is achieved. Calibration can include changing the firing, cycling, and/or associated effects (e.g., felt recoil) without rendering the autoloading firearm inoperable (e.g., due to insufficient gas reaching a moving parts assembly to complete a firing cycle reliably). If the determination at 1006 is negative, methodology 1000 recycles to 1004 where further modifications are completed using the adjustment aperture (and/or associated adjustment control).

If the determination at 1006 returns positive, the autoloading firearm is calibrated, and methodology 1000 proceeds to end at 1008.

Adjustment apertures and adjustment controls herein are generally depicted as openings or movable components there through in a gas key for an autoloading firearm. However, upon review of these disclosures, other mechanisms for modifying gas flow through a bolt carrier group will be apparent. For example, a shutter or other movable portion could be movably provided above, below, or directly on carrier interface opening 122, or at other portions of conduit 132. Different constricting mechanisms or gas keys with conduits of varying or smaller cross-sectional size can be employed to similar effect. Such alternatives are within the scope and spirit of the disclosure, one result of which is to modify firing characteristics of an autoloading firearm based on modifications to the flow of gases through the use of components housed within the upper receiver of the firearm.

While principles and modes of operation have been explained and illustrated with regard to particular embodiments, it must be understood, however, that this may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope. 

What is claimed is:
 1. A system for controlling gas flow to a moving parts assembly in an autoloading firearm cycled at least in part using gas produced from firing of the autoloading firearm, comprising: means for establishing fluid communication with a gas source providing the gas during at least one portion of a firing cycle of the autoloading firearm; a conduit of the means for establishing fluid communication including an inlet corresponding to the gas source and an outlet directing at least a portion of the gas toward the moving parts assembly; and a means for modifying the gas flow through the conduit.
 2. The system of claim 1, wherein the means for establishing fluid communication is an upper interface of an adjustable gas key.
 3. The system of claim 2, further comprising an attachment means that operatively couples the adjustable gas key with the moving parts assembly.
 4. The system of claim 2, wherein the means for modifying the gas flow is an adjustment aperture in fluid communication with the conduit incident to at least a portion of the conduit.
 5. The system of claim 4, wherein the adjustment aperture is incident to the conduit from the rear of the adjustable gas key.
 6. The system of claim 4, wherein the adjustment aperture receives an adjustment control.
 7. The system of claim 6, wherein the adjustment aperture is threaded, and wherein the adjustment control is a screw.
 8. The system of claim 6, further comprising an internal recess that receives at least a portion of the adjustment control.
 9. The system of claim 1, wherein the moving parts assembly is a lightweight moving parts assembly.
 10. A method of making an adjustable gas key for an autoloading firearm, comprising: providing a gas key having an angled portion and an upper interface, the angled portion directs at least a portion of gas from firing the autoloading firearm toward a moving parts assembly, the upper interface maintains fluid communication with a gas source during at least a portion of a firing cycle of the autoloading firearm, wherein a continuous conduit is provided through the upper interface and angled portion; and forming an adjustment aperture in fluid communication with the conduit incident to at least a portion of the conduit.
 11. The method of claim 10, further comprising arranging an adjustment control in the adjustment aperture.
 12. The method of claim 11, further comprising forming an internal recess in a portion of the conduit distinct from the portion of the conduit incident to the adjustment aperture.
 13. The method of claim 10, further comprising threading the adjustment aperture.
 14. The method of claim 11, further comprising providing a screw in the adjustment aperture.
 15. The method of claim 10, wherein the gas key is a gas key of an M-16 type rifle.
 16. A method of adjusting a firing characteristic of an autoloading firearm cycled at least in part using gas produced from firing of the autoloading firearm, comprising modifying a flow of gas resultant to firing of the autoloading firearm within a gas key.
 17. The method of claim 16, wherein modifying the flow of gas is accomplished at least in part by restricting the flow of gas through the gas key.
 18. The method of claim 17, wherein restricting the flow of gas through the gas key is accomplished at least in part by seating a screw to at least partially interrupt a conduit of the gas key.
 19. The method of claim 18, further comprising turning the screw to open or close the conduit of the gas key.
 20. The method of claim 17, wherein modifying the flow of gas is accomplished at least in part by venting at least a portion of the gas from the gas key in a direction alternative to that of a moving parts assembly of the autoloading firearm. 